We're going to turn to the terror plot across the border in canada, where officials believe they have thwarted a plan to bomb trains heading from new york. Officials believe there was some al qaeda involvement here. Reporter: Yes, they do, george. And authorities say this new plot is a sobering reminder that the threat of terror remains real and quite diverse. Terrorists are going to try to hurt us every possibly way. Reporter: This morning, this man and another suspect will appear in court to face charges for conspiring to derail a train traveling from new york to toronto, killing hundreds. The alleged plan to plant bombs to destroy the tracks and derail the trains. The target, an amtrak passenger line, which partners with cana canada's via rail. It's a busy route. The service also crosses one of the most spectacular bridges in north america. Had this plot been carried out, it would have resulted in innocent people being killed or seriously injured. Reporter: The suspects had done surveillance on trains in the toronto area. But canadian authorities, with the help of the fbi, up the plot before it became operational. Canadian authorities say they were tipped off by members of the muslim community. But authorities believe the suspects were directed by al qaeda operatives in iran. The individuals were receiving support from al qaeda elemen located in iran. Report If al qaeda operatives were to carry out a truly disastrous terrorist attack, somewhere in the world, somewhere in the west, somewhere in the united states, and it were traced back to al qaeda in iran, then that could provoke hostility. Reporter: It's part of al qaeda's playbook. Documents obtained from osama bin laden's secret compound revealed he had been urging followers to derail a train in the u.S. To kill passengers. This morning, the iranian government is skeptical, with one senior official calling the canadian claims, quote, ridiculous.

This transcript has been automatically generated and may not be 100% accurate.

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